PartialGraphHost

Kind: Class

Source: packages/core/inspector/partial-graph.host.ts

Part of: Core

PartialGraphHost is a static host for storing and exposing the most recently generated partial dependency graph. It delegates serialization to a SerializedGraph, allowing inspector and error-reporting flows to retrieve the graph as JSON or a formatted string after it has been registered.

Methods

Diagram

mermaid
graph LR
  A[Graph inspection or bootstrap failure] --> B[SerializedGraph]
  B -->|register(graph)| C[PartialGraphHost]
  C -->|toJSON()| D[Structured graph data]
  C -->|toString()| E[Human-readable graph output]

Usage

ts
import { PartialGraphHost } from '@nestjs/core/inspector/partial-graph.host';
import { SerializedGraph } from '@nestjs/core/inspector/serialized-graph';

// Typically produced by the inspector while scanning application modules.
const partialGraph = new SerializedGraph();

// Store the graph for later diagnostics or reporting.
PartialGraphHost.register(partialGraph);

// Retrieve serialized output.
const graphJson = PartialGraphHost.toJSON();
const graphText = PartialGraphHost.toString();

console.log(graphJson);
console.log(graphText);

AI Coding Instructions

• Treat PartialGraphHost as a static global holder; do not instantiate it or rely on per-instance state.
• Register a complete SerializedGraph before calling toJSON() or toString() to avoid reporting stale graph data.
• Keep serialization logic in SerializedGraph; PartialGraphHost should only store and delegate to the registered graph.
• Use this host for inspector, diagnostics, and bootstrap-error integration points where a partial dependency graph must remain accessible.
• Be aware that calling register() replaces the previously stored graph for the entire process.

How it works

• PartialGraphHost is an exported class with one private, class-level SerializedGraph reference named partialGraph. [packages/core/inspector/partial-graph.host.ts:3-4]

• register(partialGraph) assigns its SerializedGraph argument to that shared reference. A later call replaces the previously stored graph; the method contains no visible validation or error handling. [packages/core/inspector/partial-graph.host.ts:14-16]

• toJSON() optionally calls toJSON() on the stored graph. If no graph has been registered, optional chaining causes it to return undefined; it does not throw from this method. [packages/core/inspector/partial-graph.host.ts:6-8] When a graph exists, the delegated serialization contains object forms of its nodes, edges, and entrypoints, plus extras and, when set, status and metadata. [packages/core/inspector/serialized-graph.ts:125-140]

• toString() likewise optionally delegates to the stored graph. A registered SerializedGraph formats its JSON with two-space indentation, converts symbols to strings, and serializes functions as their name or "Function". [packages/core/inspector/partial-graph.host.ts:10-12] [packages/core/inspector/serialized-graph.ts:142-150]

• The in-repository registration path is GraphInspector.registerPartial(error): it marks its graph’s status as 'partial', records metadata for either an UnknownDependenciesException or an unknown error, then registers that graph with this host. [packages/core/inspector/graph-inspector.ts:38-59]